C2 noun /ˈrɛv.ər.i/
reverie
白昼の夢; 夢想
Meaning
A state of being pleasantly lost in one's thoughts; a daydream.
Example
Lost in reverie, he didn't hear his name being called.
夢想にふけっているため、彼は名前が呼ばれるのを聞かなかった。